AlN-Pr_2O_3液相烧结SiC陶瓷

Liquid Phase Sintering of SiC with AlN-Pr_2O_3 Additives

以Al N、Pr_2O_3做为SiC陶瓷液相烧结的复合助剂,选定不同的助剂含量(5wt%~20wt%)和不同的助剂摩尔比例(Pr_2O_3/Al N=1/3、1/1、3/1),在1800~2000℃温度下,采用热压和无压烧结的方法制备SiC陶瓷样品,并对这些陶瓷样品的性能进行了研究。实验结果表明,助剂比1/3组的样品显示出更有效地促进SiC陶瓷致密化,该组样品无压烧结最大相对密度为87%,热压烧结具有最高的相对密度96.1%、维氏硬度23.4 GPa、抗弯强度549.7MPa、断裂韧性5.36 MPa·m1/2,显微结构中可观察到晶粒拔出现象,断裂模式为沿晶断裂。

In present work, samples of SiC ceramic with AlN-Pr203 additives in different content （Swt%- 20wt% ） and different mole ratio （Pr2O3/AlN = 1/3, 1/1, 3/1 ） were prepared by hot pressed （HP） and pressureless sintering at 1800-2000 ℃, and its performance were investigated. The results show that samples in group 1/3 can promote the densification of SiC ceramics more effectively. The maximal relative density of 1/3 group is 87% by pressureless sintering, while the supreme relative density, hardness, flexure strength and fracture toughness are achieved by HP, as 96.1% , 23.4 GPa, 549.7 MPa, 5.36 MPa.m1/2 , respectively. Phenomenon of grain pull-out is observed in mierostructure and the fracture mode is intergranular fracture.